1. Field of the Invention
The present invention relates to a camera-attached mobile apparatus, and more particularly, to a mobile apparatus that changes a display orientation of a display object according to a user's viewing direction.
2. Description of Related Art
There are mobile apparatuses that change a display orientation of a display object in accordance with a user's viewing direction (for example, see JP-A-2008-177819 and JP-A-2003-186462). Such mobile apparatuses disclosed in the above-described publications detect a direction of a user's face by using a camera mounted on the mobile apparatus and displays an image, text, or the like in a orientation that coincides with the orientation of the user's face. Accordingly, the display orientation of the display image coincides with the orientation of the user's face without depending on the user's posture or holding method of the mobile apparatus, and thereby the display image can be easily viewed by the user.
As described in JP-A-2008-177819, when an e-mail is received and a display is directed by an input operation in a mobile apparatus, a camera is activated. Thus, a face image is photographed by the camera, a vertical orientation of the face image is determined, and a display orientation of communication data is controlled coincidentally with the vertical orientation of the face image. Then, until the display of the communication data of the e-mail is completed, the face image continues to be photographed by the camera so as to respond to a change in the orientation of the user's face. In addition, when a browser is activated in accordance with an input operation, the camera is activated. Thus, a face image is photographed by the camera, the vertical orientation of the face image is determined, and a display orientation of a browser image is controlled coincidentally with the vertical orientation of the face image. Then, until the display of the browser is completed, the face image continues to be photographed by the camera so as to respond to a change in the orientation of the user's face.
However, in JP-A-2008-177819, the camera is activated all the time in a display state, and accordingly, a power consumption of the camera is large. Therefore, power of a battery of the mobile apparatus is rapidly consumed.
In addition, as described in JP-A-2008-177819, in a case where an orientation of a user's face shown is tilted by an angle θ, an image is generated so as to be tilted by the angle θ in the same orientation as the orientation of the user's face and is displayed on a screen.
In a case where the user views the screen, the orientation of the user's face and a display orientation of the image coincide with each other, and accordingly, the user may easily view the image. However, there are cases where the user has an uneasy feeling when the image is displayed as tilted with respect to a rectangular frame of the screen.